Disable xchat autocomplete without tab

This leads to a lot of accidental channel spam. Hitting tab isn't hard.
Honestly, I have no clue why anyone would ever want to turn this on.
General email improvements

-   Extend postgrey whitelist
-   Fix issues with hotmail and comcast.net
-   Increase process and client limit "sanity checks"
-   Compress email with bzip2
-   Remove emails to `root` from the inbox and place them in a folder

This is the setup I've been using for nearly a week, and it seems pretty
solid.